The player, himself, was tickled pink by his achievement after downing Germany’s Maximilian Marterer 5-7 6-3 7-5 7-6(5) on Saturday to be the last man standing of 13 Americans in the draw.

“It’s kind of silly, right? It feels kind of silly,” the 97th-ranked Tennessee native told reporters after his nearly three-hour win at a raucous Show Court Two.

“I didn’t think I’d make the second week when I came here. I was hoping to play a few good matches or try to get my first win, things like that.

“But to realistically set my sights on a second week wasn’t on the cards.”

Just by getting to the second round, 26-year-old Sandgren beat the odds, making the breakthrough in just his third grand slam main draw appearance after first round exits at the U.S. Open and Roland Garros last year.

Fortune has played a part, with his second round victim Stan Wawrinka, a three-times grand slam champion, clearly restricted by his lingering knee injury in defeat.

The 94th-ranked Marterer proved a willing, if possibly reduced opponent following the German’s taxing five-set win over Spanish veteran Fernando Verdasco in the previous round.

Sandgren has been dealt a decent set of cards but it would be churlish to downplay the achievement of a lower-ranked battler more used to road trips across America for minor tour events than jetting across the globe to soak up the glamour of the grand slams.

A fourth round appearance means a A$240,000 ($192,000) cheque, nearly half the total prize money in his career, and a potentially life-changing leap in rankings.

“I guess short-term is that it looks good for me for Roland Garros, I think, which is fantastic,” he said. “Things like that, just getting in more main draws, more opportunities to play well, see what I’m capable of is a big deal.”

UNCONVENTIONAL PATH

Even after slicing off his pony-tail and shaving his mustache last year, Sandgren seems cut from a different cloth compared to contemporary players tailored by academy teaching and elite pathways.

He was coached and home-schooled by his South Africa-born mother until he went to college, and “butted heads” with her for years as a “feisty” and “more negative version” of his modern-day self.

He now admits he has tried to clean up his image to be a little more professional.

“I don’t feel much like corporate tennis, but maybe quicker shower tennis,” said Sandgren, wearing a black T-shirt emblazoned with the name of metal band Metallica.

“I don’t have to use as much shampoo, which is good.”

He will meet Austrian fifth seed Dominic Thiem for a place in the quarter-finals. It will be a massive challenge but Sandgren feels like he is already playing with house money.

“It would be cooler if I could go a little farther, make a real result,” he said.

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“To be the last (American) out of that group is pretty cool.

“Just adds to the weight of kind of how this feels to be in the second week of a slam.”